The Indiana State sentinel. [volume] (Indianapolis) 1868-1895, 1887-08-24
EARTHQUAKES.

of which is variously estimated, matter is
in the condition OF lava, which volc Inoes
vomit forth. 1t has been shown by pub
lished catalogues of earthquakes, extend
ing over period of more than two hun
bred years, that earthquakes occur at an
average rate of about twenty-five a year.
The probability that the earth will event
uallv become solid from center to -circum-
ference, is quite too remote to excite COM
ment-and with the exception of earth
quake calamities, is of questionable de
STABILITY, since were it not for the internal
heat of the earth, there might be such a
condition of things upon the surface, as to
make earthquakes desirable as the lesser
evil.
A great deal of superior prose and poetry
has been written, describing and eulogiz-
ing the diversified condition of the earth's
surface. The hills and the valleys noun
tains, canyons, and gorges have furnished
themes for writers and ceaseless satisfaction
to tourists, and these wonders OF creation,
these sublime exhibitions of power and
energy, are largely attributable to earth
euakes-and therefore there msy be soma
qualification in the assumption that after
all earthquakes are not an unmixed evil;
that the good they do in identifying the
earth's surface, is compensation for the
comparatively small harm in the destruc-
ton of occasional city or village.
While 1t is admitted that earthquakes
would not ocour if the center of the earth
were not liquid fire, various theories are
Gus influences in operation which produce
earthquake periods, among which the most
potent in the opinion of some investigators
are sun-spots, that is to say, when there are
msnv spots on the sun, earthquakes may
be expected to abound. and when there is
an absence of sun-spots, the danger from
seismic disturbances may be said 10 be re-
duced to the lowest degree. As no one
knows what sun-spots are, or why they are,
not even the most advanced scientists, it
becomes very convenient to charge earth
quakes to their account. But in
vestigators Of the sun-spot the.
ory widely disagree, as for in
stance, while Wolf came to the con
clusion that the earthquake records ex.
hibit period of about eleven years be-
tween the successive maxima, correspond
ing to the sunspot cycle, the maximum of
earthquakness coiBciding with the maxi
mum of sun-spottiness. But KIuge
whose investigations come in later, found
that earthquakes attain their maximum
when sun-spots are fewest, and a third in
vestigstor, Mr.. Poey, detects two earth
quake maxima, one, when sun-spots are
most numerous, aud the other when sun
spots are fewest. Thus, these investigators
completely upset the sun-spot theory, and
some other outside influence is required.
As result, we have il stated that the
moon is the cause of much of the mischief
In this connection we quote from an ar.
ticle by John A. Westwood Oliver, printed
in the Eclectic Magazine tor August. The
writer says:
The idea that the moon should have
something to do with the production of
earthquakes, Is very nataral one. The
body whose attractive power raises the
ocean tides exercises its influence on the
dry land just Is much as on the sea, and
the only reason why the land does not res
pond to the attraction is because of its
immobiity, But force so resisted means
internal strain, and We have every reason
to believe that, corresponding to the tide
of movement on the ocean, tnere is q tide
strain on the land. How may this strain
make itself apparent? A breath of autumn
air brings down the leaves that have with
stood a summers gales, a Swapping twig
| has loosed the Alpln avalanche. The crust
OF our earth is not solid. There are cavi-
/ ties and assures lin its mass, frail places
where only a touch as it were, may cause
collapse; and the series of changes so begun
may involve continent In ruin before il
is ended And the tidal strain, as it passes
regulsTly sruond the globe, may one day
supply Just the needed touch, thus becom-
ing an agent of destruction none the less
potent because it only plays the part of
trigger puller. The theory is plausible,
and to q certain extent the researches of
Professor Perry bear it out. He found
that the earthquakes are rather more fire.
quent when the tidal pull is s.rong-that
is, when sun and moon are pulling in line
lat new or full NOON, and when the moon
is in the part OF her orbit nearest TO the
earth fperigsel. The difference however
vas only small, and as other Investigator!
have arrived at contradictory results, the
lunar theory "a this form has not held it
ground.
"Falb has gwen 1t different shape. HI
assumes that the earth has a fluid interior
and that in the inner surface OF the soliC
crust there are cracks and channels. Ii
the fluid mass there are tides raised by thu
attraction Of the-sun and moon, and tn
effect of the tides Is to cause the moltol
matter TO ebb and flow in the riits ant
chasms, Just like the sea in our bays az
estuaries. When the hot matter enters tn
solid and comparatively cold channels il
the earth's crust 1t is rapidly cooled, an,
explosions Of gas and subterranean vol
canic disturbances result. The violence 0
these phenomena depends on the height o
the internal tides, and as that In turn dc
Ponds upon the relative position and dil
lance at any time Of the sun and moon